Crossbow assembly

0001The present application is a continuation of U.S. patent application Ser. No. 15/929,346 filed Apr. 28, 2020, which claims the benefit of U.S. provisional application No. 62/844,182 filed on May 7, 2019, both of which are incorporated herein by reference.

FIELD OF THE INVENTION

0002The present disclosure relates generally to crossbows.

BACKGROUND OF THE INVENTION

0003Crossbows have been used for centuries for both hunting and recreation. They are typically characterized by horizontal limbs mounted on a stock with a bowstring that is drawn to store energy. The bowstring is drawn over the rail and held in a latch that holds the bowstring until the user is ready to fire. When the user is ready to shoot an arrow (alternately referred to as a bolt or quarrel), the user pulls a trigger. Upon pulling the trigger, a series of interactions occurs between components of a trigger assembly, allowing the bowstring to be released from the latch and allowing transfer of stored energy to the arrow.

0004There are several different designs of crossbows. A traditional crossbow has flexible limbs that extend laterally in a horizontal plane. The butt portions or anchor ends of the limbs are mounted adjacent the forward end of a stock or rail. A bowstring extends between the outer limb tips. When the bowstring is drawn, the limbs deflect rearward and inward and store potential energy that is transferred to the bowstring and an arrow when the crossbow is fired. A traditional crossbow can be a recurve style where the bowstring is connected directly to the limb tips or a compound crossbow which has a set of wheels or cams attached to its limbs. In a compound crossbow, a cabling system attached to the wheels or cams is used to assist in bending the limbs as the bowstring is drawn.

0005A variation is a reverse style crossbow. A typical reverse crossbow has flexible limbs that extend laterally in a horizontal plane, yet the butt portions or anchor ends of the limbs are mounted closer to the user. The limbs curve outward and forward away from the user. When cocked, the limb tips are drawn generally forward and inward toward a central portion. When released, the limb tips spring laterally outward, causing the bowstring to travel forward and propel a projectile such as an arrow. Examples of reverse crossbows are shown in U.S. Pat. No. 3,108,583 to Andis; U.S. Pat. No. 5,630,405 to Nizov; U.S. Pat. No. 4,169,456 to Van House; U.S. Pat. No. 4,766,874 to Nishioka; U.S. Pat. No. 4,879,987 to Nishioka; U.S. Pat. No. 7,328,693 to Kempf, and U.S. Pat. No. 7,938,108 to Popov.

SUMMARY

0006Certain embodiments of the present crossbow assembly use an arrangement with two pairs of limbs, with one pair of opposing limbs on each side of the stock. The two limbs within each pair are parallel yet arranged in opposition to each other in a vertical plane. The rearward ends of the limbs are anchored with the limb tips being free to move. The limb tips are each connected to an axle assembly with respective limb cables. As the axle assembly is turned it wraps the limb cables around the axle shaft, drawing the limb tips vertically together to store energy, which, when released, causes the axle assembly to rotate to unwind the cables.

0007At opposing ends of the axle assembly a pair of axle pulleys are arranged in vertical planes. The crossbow includes a bowstring with opposing ends having one end connected to each axle pulley. An intermediate portion of the bowstring extends forward from each axle pulley and extends across the stock, passing between two bowstring pulleys which are arranged in a horizontal plane. The middle of the bowstring forms the nock point, which can be drawn rearward over the rail between the two bowstring pulleys to a latch assembly.

0008In the brace or undrawn position, the end portions of the bowstring are each wrapped around a respective axle pulley. As the nock point of the bowstring is drawn rearward, the bowstring is unwrapped to feed out from the axle pulleys, causing the axle pulleys to turn and correspondingly rotate the axle shaft. Rotation of the axle shaft winds the limb cables inward to draw the limb tips towards the axle shaft. Upon releasing or firing the crossbow, the nock point of the bowstring is released, allowing the intermediate bowstring portion to translate forward to launch the arrow. Via a linkage of components, the release allows the stored energy in the limbs to be released, allowing the limbs to spring vertically upward and downward and in turn causing the limb cables to unwind from the axle shaft. This causes the axle pulleys to wind the bowstring ends into the respective axle pulleys. The stored limb energy is thus transferred to the nock point of the bowstring and converted to kinetic energy to propel the arrow.

0009In one illustrative embodiment a crossbow assembly includes a stock with a rail defining a forward direction and defining a bolt guide to guide an arrow. A trigger and latch assembly are housed in the stock and the rail wherein the latch mechanism is configured to selectively retain the nock point of a bowstring until it is released by operation of the trigger. A first limb cup and a second limb cup extend from the stock and arranged on opposing lateral sides of the rail. A first pair of limbs has butt ends mounted to the first limb cup and a second pair of limbs has butt ends mounted to the second limb cup. The first pair of limbs are vertically aligned and arranged to flex with opposing directional forces and the second pair of limbs are vertically aligned and arranged to flex with opposing directional forces. An axle assembly is rotationally mounted adjacent to and underneath a forward end of the rail, the axle assembly including a shaft and a pair of axle pulleys arranged at opposing ends of the shaft. the limb tip of each limb is connected to the axle assembly via a series of limb cables. A pair of bowstring pulleys is arranged adjacent a forward end of the rail on opposing lateral sides of the rail. The bowstring has a nocking point centrally arranged between the bowstring pulleys and arranged to be drawn over the rail to the latch assembly. The bowstring extends from the nocking point to the bowstring pulleys and then along the opposing lateral sides of the rail. The bowstring has two ends with one end engaging each axle pulley.

0010In an alternate illustrative embodiment, a crossbow assembly has a stock with a rail defining a bolt guide to guide an arrow. A trigger and latch assembly is housed in the stock and the rail. The latch mechanism is configured to selectively retain the nock point of a bowstring until it is released by operation of the trigger. A first limb cup and a second limb cup extend from the stock and are arranged on opposing lateral sides of the rail. A first pair of limbs has butt ends mounted to the first limb cup and a second pair of limbs has butt ends mounted to the second limb cup. The first pair of limbs are vertically aligned and arranged to flex with opposing directional forces and the second pair of limbs are vertically aligned and arranged to flex with opposing directional forces. The bowstring is configured to be drawn over the rail to the latch assembly. The bowstring is operationally linked to the first pair of limbs and the second pair of limbs such that when the bowstring is drawn, the limb tips of the first pair of limbs move towards each other and the limb tips of the second pair of limbs move towards each other. When the bowstring is released, the limb tips of the first pair of limbs move away from each other and the limb tips of the second pair of limbs move away from each other.

0011In a further illustrative embodiment, a crossbow assembly includes a stock with a rail defining a bolt guide. A trigger and latch assembly is housed in the stock and the rail. The latch mechanism is configured to selectively retain a bowstring drawn over the rail until the bowstring is released by operation of the trigger. A first limb cup and a second limb cup are arranged on opposing lateral sides of the rail. A first pair of limbs has butt ends mounted to the first limb cup and a second pair of limbs has butt ends mounted to the second limb cup. The first pair of limbs are vertically aligned and arranged to flex with opposing directional forces and the second pair of limbs are vertically aligned and arranged to flex with opposing directional forces. An axle assembly is rotationally mounted to the stock. A limb tip of each limb is connected to the axle assembly via a series of limb cables. The bowstring has two ends with each end engaging the axle assembly.

0012Additional objects and advantages of the described embodiments are apparent from the discussions and drawings herein.

BRIEF DESCRIPTION OF THE DRAWINGS

0013<figref idref="DRAWINGS">FIG. 1</figref> is a perspective view of a crossbow assembly in an undrawn position illustrating an embodiment of the present disclosure.

0014<figref idref="DRAWINGS">FIG. 2</figref> is an exploded view of the crossbow assembly of <figref idref="DRAWINGS">FIG. 1</figref>.

0015<figref idref="DRAWINGS">FIG. 3</figref> is a side view of the crossbow assembly of <figref idref="DRAWINGS">FIG. 1</figref>. The opposite side is symmetric.

0016<figref idref="DRAWINGS">FIG. 4</figref> is a top view of the crossbow assembly of <figref idref="DRAWINGS">FIG. 1</figref>.

0017<figref idref="DRAWINGS">FIG. 5</figref> is a front view of the crossbow assembly of <figref idref="DRAWINGS">FIG. 1</figref>.

0018<figref idref="DRAWINGS">FIG. 6</figref> is a partial view of the crossbow assembly of <figref idref="DRAWINGS">FIG. 1</figref> illustrating the interaction of the limbs, the axle assembly and the limb cables. Other portions of the crossbow assembly are not shown in <figref idref="DRAWINGS">FIG. 6</figref> for ease of illustration.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

0019For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments illustrated and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alterations, modifications, and further applications of the principles being contemplated as would normally occur to one skilled in the art to which the invention relates.

0020Certain embodiments of the present crossbow assembly use an arrangement with two pairs of limbs, with one pair of opposing limbs on each side of the stock. The two limbs within each pair are parallel yet arranged to flex in opposition to each other in a vertical plane. The rearward ends of the limbs are anchored while the limb tips of the limbs are free to move. The limb tips are each connected to an axle assembly with respective limb cables. As the axle assembly is turned it wraps the limb cables around the axle shaft, drawing the limb tips vertically together to store energy, which, when released, causes the axle assembly to rotate to unwind the cables.

0021At opposing ends of the axle assembly a pair of axle pulleys are arranged in vertical planes. The crossbow includes a bowstring with opposing ends having one end connected to each axle pulley. An intermediate portion of the bowstring extends forward from each axle pulley and extends across the stock, passing between two bowstring pulleys which are arranged in a horizontal plane. The middle of the bowstring forms the nock point, which can be drawn rearward between the two bowstring pulleys and over the rail to a latch assembly.

0022In the brace or undrawn position, the end portions of the bowstring are each wrapped around a respective axle pulley. As the nock point of the bowstring is pulled rearward, the bowstring is unwrapped to feed out from the axle pulleys, causing the axle pulleys to turn and correspondingly rotate the axle shaft. Rotation of the axle shaft winds the limb cables around the shaft to draw the limb tips towards the axle shaft. Upon releasing or firing the crossbow, the nock point of the bowstring is released, allowing the intermediate bowstring portion to translate forward to launch the arrow. Via the linkage of components, the release of the bowstring allows the stored energy in the limbs to be released, causing the limbs to spring vertically upward and downward causing the limb cables to unwind from the axle shaft. This causes the axle pulleys to wind the bowstring ends into the respective axle pulleys. The stored limb energy is thus transferred to the nock point of the bowstring and converted to kinetic energy to propel the arrow.

0023<figref idref="DRAWINGS">FIGS. 1-5</figref> illustrate a crossbow assembly <b>10</b> shown in perspective, exploded, side, top and front views. The crossbow assembly <b>10</b> includes a stock <b>20</b> with a rail <b>40</b>. A trigger and latch assembly <b>38</b> is housed in the stock and rail and extends between the stock and rail.

0024The stock <b>20</b> generally defines a forward end and a butt end <b>22</b>. For the purposes of this disclosure, the forward direction of the crossbow assembly <b>10</b> is defined as being in the direction of shooting. The rearward direction is defined as being toward the butt end <b>22</b> of the crossbow. Directional references herein are for ease of illustration and are not intended to be limiting.

0025Stock <b>20</b> can be assembled as one or more pieces. The butt end <b>22</b> is at the rearward end of stock <b>20</b> and forms the rearward end of the crossbow assembly <b>10</b>. Optionally a butt pad <b>24</b> can be mounted on butt end <b>22</b> to be arranged against the user's shoulder during use. The stock <b>20</b> extends forward to central section <b>26</b>. Central section <b>26</b> typically provides the user with a place to hold the crossbow assembly <b>10</b>, such as grip <b>32</b>. In the embodiment shown, stock <b>20</b> also includes a forwardly placed handle <b>34</b>. A trigger guard section <b>30</b> is arranged in central section <b>26</b> between the grip <b>32</b> and handle <b>34</b>.

0026In alternate embodiments, forwardly placed handle <b>34</b> may be a separate piece spaced and mounted forward of the trigger guard, or handle <b>34</b> may be omitted. Optionally as a separate piece, the position of the handle may be selectively adjusted forward or rearward for the user's comfort, for example by sliding the handle along the bottom of an accessory rail extending along the lower surface of rail <b>40</b> and then locking it in a desired location with a clamp or screws. Optionally, the handle may be asymmetric and reversibly mountable, for example with one end having a more horizontal aspect and the other end having a more vertical aspect, which can be arranged to match a user's desired orientation.

0027In the embodiment shown, rail <b>40</b> is attached on top of stock <b>20</b> and is partially received within a channel or cavity <b>28</b> in central section <b>26</b>. The upper surface and longitudinal axis of rail <b>40</b> defines a bolt guide, for example a pair of rails on opposites sides of a groove, upon which the shaft of an arrow or crossbow bolt can rest and which guides the arrow when it is released. Rail <b>40</b> includes a rearward end <b>42</b> partially received within cavity <b>28</b> in stock <b>20</b>, for example adjacent the rearward portion of trigger guard section <b>30</b> and grip <b>32</b>. The forward end <b>44</b> of rail <b>40</b> may extend past the forward end of stock <b>20</b>. In other embodiments, stock <b>20</b> may extend along the length of the entire rail <b>40</b>, or stock <b>20</b> and rail <b>40</b> may be formed as a single piece. In certain embodiments, rail <b>40</b> has a hollow interior. Rail <b>40</b> can be made of metal, for example using aluminum. The rail can be extruded, with desired fastener holes, slots and other openings cut or machined after the extrusion process.

0028Optionally, a rail cap can be used to close the forward end <b>44</b> of rail <b>40</b>. Further optionally, rail <b>40</b> may include an accessory mounting rail, sometimes called a picatinny rail, for example on the lower side of rail <b>40</b> adjacent to forward end <b>44</b>. Finger guards may optionally be mounted on opposing sides of rail <b>40</b>, for example adjacent and parallel to handle <b>34</b>.

0029The trigger and latch assembly <b>38</b> is partially housed within the cavity <b>28</b> and extends above and below rail <b>40</b>. A pivotal trigger extends downward through a trigger slot defined in the rail <b>40</b> and stock <b>20</b>, within the space defined by the trigger guard section <b>30</b>. A trigger linkage operatively extends within stock <b>20</b> and rail <b>40</b> between the trigger and latch assembly <b>38</b>. Latch assembly <b>38</b> includes a latch mechanism which can receive and selectively retain the nock point <b>172</b> of bowstring <b>170</b> and the rear portion or nock of a crossbow arrow on top of rail <b>40</b>. Latch assembly <b>38</b> holds the bowstring <b>170</b> and arrow until it is released when a user operates or pulls the trigger.

0030When the bowstring <b>170</b> is drawn rearward over rail <b>40</b>, the nock point <b>172</b> is pulled into latch assembly <b>38</b>, where it is held until the trigger is operated to fire the arrow. The arrow then travels forward along the axis of the bolt guide of rail <b>40</b>. The latch assembly may include appropriate internal operating mechanisms as well as safety mechanisms to prevent unintended release and an anti-dryfire mechanism. A variety of trigger and latch mechanisms are available and any suitable mechanism for firing an arrow from crossbow assembly <b>10</b> may be chosen.

0031A pair of first and second limb cups <b>50</b> is arranged on opposing lateral sides of rail <b>40</b>. Limb cups <b>50</b> may be integrally formed with stock <b>20</b> and rail <b>40</b> or may be made separately and attached. In the illustrated embodiment, limb cups <b>50</b> are arranged toward the rear of rail <b>40</b>, for example close to latch assembly <b>38</b> and/or trigger guard section <b>30</b>. The limb cups <b>50</b> are laterally offset from rail <b>40</b> with a pair of support extensions. Each limb cup <b>50</b> includes a pair of cavities defining a pair of limb pockets <b>56</b>. In the illustrated embodiments, each limb cup <b>50</b> includes an upward facing limb pocket <b>56</b> and a downward facing limb pocket <b>56</b>. The limb pockets <b>56</b> in each limb cup <b>50</b> are vertically aligned and symmetrically arranged in opposition to each other.

0032A first pair of opposing limbs and a second pair of opposing limbs are on each lateral side of stock <b>20</b> and rail <b>40</b>. In the illustrated embodiments, all of the limbs are parallel to rail <b>40</b>. For instance, <figref idref="DRAWINGS">FIGS. 1-5</figref> illustrate a first pair of limbs <b>152</b><i>a</i>, <b>152</b><i>b </i>on one side of rail <b>40</b> and a second pair of limbs <b>154</b><i>a</i>, <b>154</b><i>b </i>on the opposite side of rail <b>40</b>. The first pair of limbs includes an upper limb <b>152</b><i>a </i>and a lower limb <b>152</b><i>b</i>. Correspondingly, the second pair of limbs includes an upper limb <b>154</b><i>a </i>and a lower limb <b>154</b><i>b</i>. The limbs within each pair are vertically aligned and balanced, yet arranged to flex with opposing directional forces. For instance, during the draw cycle the limb tips move towards each other at the same rate, while when released the limb tips move away from each other at the same rate. Among other aspects, the limbs flexing in opposite vertical directions serves to minimize vertical rebound forces when crossbow assembly <b>10</b> is fired.

0033Within each pair, the limbs are vertically aligned or stacked and symmetrically arranged in opposition to each other. As illustrated, upper limb <b>152</b><i>a </i>extends forward from a butt end <b>156</b> with a downwardly concave shaped curve to limb tip <b>158</b>. As a mirror image, lower limb <b>152</b><i>b </i>extends forward from a butt end <b>156</b> with an upwardly concave shaped curve to limb tip <b>158</b>. The butt end <b>156</b> of upper limb <b>152</b><i>a </i>is received and retained in an upward facing limb pocket <b>56</b>. The butt end <b>156</b> of lower limb <b>152</b><i>b </i>is received and retained in a downward facing limb pocket <b>56</b>. The second pair of limbs <b>154</b><i>a</i>, <b>154</b><i>b </i>are arranged in a similar manner on the opposite side of rail <b>40</b>.

0034Axle assembly <b>130</b> (best seen in <figref idref="DRAWINGS">FIG. 6</figref>) is rotationally mounted adjacent to and underneath the forward end of rail <b>40</b>. Axle assembly <b>130</b> may be formed as one integral piece or may be an assembly of connected pieces. Axle assembly <b>130</b> includes a horizontal axle shaft <b>132</b>. A pair of optional drum or spool portions <b>134</b> with a larger diameter than shaft <b>132</b> may be fixedly mounted along the length of shaft <b>132</b>. A pair of axle pulleys or cams <b>136</b> are fixedly arranged at opposing ends of shaft <b>132</b>. Axle pulleys <b>136</b> define peripheral grooves <b>138</b>. The planes in which axle pulleys <b>136</b> rotate are a pair of parallel vertical planes. The vertical planes are perpendicular to the rotational axis of shaft <b>132</b>. In some embodiments, axle assembly <b>130</b> is rotationally mounted to rail <b>40</b> via a pair of mounting flanges or bosses <b>54</b> which may include bushings. Bosses <b>54</b> extend laterally to either side of rail <b>40</b>. Bosses <b>54</b> may be integrally made with rail <b>40</b> or may be made separately and mounted to rail <b>40</b>. Shaft <b>132</b> is supported adjacent its opposing ends by bosses <b>54</b>.

0035A pair of supports <b>58</b> are arranged adjacent the forward end <b>44</b> of rail <b>40</b>. In certain embodiments, each support <b>58</b> is formed by two struts which extend from rail <b>40</b> to form a triangle. Supports <b>58</b> may be integrally made with rail <b>40</b> or may be made separately and mounted to rail <b>40</b>. Supports <b>58</b> are typically arranged level with or below the level of the upper surface of rail <b>40</b>. A pair of mounting locations <b>60</b> is defined at offset outer points of supports <b>58</b>. For example, the mounting locations <b>60</b> may be located at the outer corners when supports <b>58</b> are triangles. A pair of bowstring pulleys or cams <b>120</b> are symmetrically mounted relative to rail <b>40</b> and rotationally mounted at the mounting locations <b>60</b>. The planes in which the bowstring pulleys <b>120</b> rotate are horizontal and co-planar. Bowstring pulleys <b>120</b> define peripheral grooves <b>122</b>, which are aligned with the height of an arrow shaft on rail <b>40</b>. The plane of bowstring pulleys <b>120</b> is perpendicular to the vertical planes of axle pulleys <b>136</b>.

0036A cable system including a bowstring and a series of limb cables operationally links the limbs, the axle shaft, the axle pulleys, the bowstring pulleys and the latch assembly. As illustrated in detail in <figref idref="DRAWINGS">FIG. 6</figref>, the limb tip <b>158</b> of each limb is connected to axle assembly <b>130</b> via a series of limb cables. For instance, the limb tips <b>158</b> of upper limbs <b>152</b><i>a </i>and <b>154</b><i>a </i>are each secured to an end of a respective first and second upper limb cable <b>160</b><i>a</i>. The opposing end of each upper limb cable <b>160</b><i>a </i>is mounted to shaft <b>132</b>, with a medial portion of the upper limb cable <b>160</b><i>a </i>wrapped around shaft <b>132</b>. Optionally, the shaft end and medial portion of each upper limb cable <b>160</b><i>a </i>may be wrapped around a respective drum portion <b>134</b>. The diameter of drum portions <b>134</b> can be selectively chosen and/or modified to control the ratio of the length that each limb cable is wrapped or unwrapped to the rotational degree of change in the axle shaft.

0037In a mirror image, the limb tips <b>158</b> of lower limbs <b>152</b><i>b </i>and <b>154</b><i>b </i>are each secured to an end of a respective first and second lower limb cable <b>160</b><i>b</i>. The opposing end of each lower limb cable <b>160</b><i>b </i>is mounted to shaft <b>132</b>, with a medial portion of the lower limb cable <b>160</b><i>b </i>wrapped around shaft <b>132</b>. Optionally, the shaft end and medial portion of each lower limb cable may be wrapped around a respective drum portion <b>134</b>. Upper limb cables <b>160</b><i>a </i>and lower limb cables <b>160</b><i>b </i>are symmetrically arranged in direction around shaft <b>132</b> so that they all wrap around shaft <b>132</b> when the axle assembly <b>130</b> is rotated in one direction (counter-clockwise from the perspective of <figref idref="DRAWINGS">FIG. 3</figref>), and all unwrap from shaft <b>132</b> when axle assembly <b>130</b> is rotated in the opposite direction (clockwise from the perspective of <figref idref="DRAWINGS">FIG. 3</figref>).

0038Bowstring <b>170</b> has a nocking point <b>172</b> centrally arranged between bowstring pulleys <b>120</b> and aligned in height with the nock of an arrow on rail <b>40</b>. Bowstring <b>170</b> extends laterally in two directions from nocking point <b>172</b>, with respective lateral portions received in grooves <b>122</b> of bowstring pulleys <b>120</b>. Bowstring pulleys <b>120</b> each turn bowstring <b>170</b> in substantially a 90 degree turn. From bowstring pulleys <b>120</b>, bowstring <b>170</b> extends rearward on both sides of rail <b>40</b>, with the opposing bowstring ends each engaging and secured to a respective axle pulley <b>136</b>. A portion of bowstring <b>170</b> adjacent to each opposing end forms a wrapped portion <b>174</b> received in a respective axle pulley groove <b>138</b> and extending at least partially around the circumference of each axle pulley <b>136</b>. The specific length of wrapped portion <b>174</b> varies depending on whether crossbow assembly <b>10</b> is in a drawn or released position. In the illustrated embodiments, the upper portions of axle pulley grooves <b>138</b> are aligned in a horizontal plane with bowstring pulley grooves <b>122</b>. This orients the bowstring <b>170</b> so that the portions between bowstring pulleys <b>120</b> and axle pulleys <b>136</b> extend and travel in lines parallel to the longitudinal axis of rail <b>40</b>.

0039Wrapped portions <b>174</b> are arranged in direction around axle pulleys <b>136</b> so that when nocking point <b>172</b> is drawn rearward, bowstring <b>170</b> translates forward and inward around bowstring pulleys <b>120</b>, causing portions <b>174</b> to unwrap from the respective axle pulleys <b>136</b>. Simultaneously upper limb cables <b>160</b><i>a </i>and lower limb cables <b>160</b><i>b </i>wrap around shaft <b>132</b> consequently drawing limb tips <b>158</b> towards axle shaft <b>132</b>. Conversely, when nocking point <b>172</b> travels forward, bowstring <b>170</b> translates outward and rearward around bowstring pulleys <b>120</b>, allowing more length to be wrapped around respective axle pulleys <b>136</b>. Simultaneously upper limb cables <b>160</b><i>a </i>and lower limb cables <b>160</b><i>b </i>unwrap from shaft <b>132</b> allowing limb tips <b>158</b> to travel away from axle shaft <b>132</b>.

0040During the draw cycle of crossbow assembly <b>10</b>, nocking point <b>172</b> is drawn rearward between forward pulleys <b>120</b> and secured by latch assembly <b>38</b>. The crossbow components are operationally linked so that during the draw cycle, force applied to draw nocking point <b>172</b> rearward causes motion in the bowstring, the bowstring pulleys, the axle assembly and the limb cables to flex the limbs to store energy in the limbs. Once bowstring <b>170</b> is fully drawn and latched, an arrow is inserted onto the bolt guide on rail <b>40</b>, and the rear end or nock of the arrow is positioned on bowstring <b>170</b> at nocking point <b>172</b>. Once the arrow is positioned, the crossbow assembly <b>10</b> is ready to be fired upon release of any safeties and proper operation of the trigger. When a user pulls the trigger to fire the crossbow, latch assembly <b>38</b> releases nocking point <b>172</b>. Via the operationally linked assembly components, the stored energy in the limbs applies force via limb cables <b>160</b><i>a </i>and <b>160</b><i>b </i>to rotate the axle assembly, which in turn rotates axle pulleys <b>136</b> to pull and wrap portions of bowstring <b>170</b> to translate outward and rearward around bowstring pulleys <b>120</b>, thus transmitting force to an arrow at nocking point <b>172</b>.

0041In alternate embodiments, a variation of crossbow assembly <b>10</b> could be made with only one pair of limbs, with one limb on either lateral side of stock <b>20</b> and rail <b>40</b>. For instance, such embodiments could use only upper limbs <b>152</b><i>a</i>, <b>154</b><i>a </i>or only lower limbs <b>152</b><i>b</i>, <b>154</b><i>b</i>. This would apply asymmetric loads to the end of axle assembly <b>130</b>, and may require a stronger axle assembly to prevent the axle from bending. An arrangement with only an upper pair of limbs or only a lower pair of limbs would correspondingly clear the area under the rail or above the rail. An illustration of an embodiment with only upper limbs <b>152</b><i>a</i>, <b>154</b><i>a </i>would correspond to <figref idref="DRAWINGS">FIG. 6</figref> with lower limbs <b>154</b><i>b</i>, <b>152</b><i>b</i>, and cables <b>160</b><i>b </i>removed. Conversely, an illustration of an embodiment with only lower limbs <b>152</b><i>b</i>, <b>154</b><i>b </i>would correspond to <figref idref="DRAWINGS">FIG. 6</figref> with upper limbs <b>154</b><i>a</i>, <b>152</b><i>a</i>, and cables <b>160</b><i>a </i>removed. Corresponding modifications would be made to the embodiment illustrated in <figref idref="DRAWINGS">FIGS. 1-5</figref>.

0042Crossbow assembly <b>10</b> as illustrated in <figref idref="DRAWINGS">FIGS. 1-5</figref> is a reverse crossbow, in the sense that the limb butts are mounted at rearward locations and the limb lengths extend forward. In alternate embodiments, the limb butts could be mounted at forward locations, with the limb lengths extending rearward. A corresponding modification to the location of axle assembly <b>130</b> would be needed. In further alternate embodiments the limb orientation could be modified, for instance with two pairs of limbs arranged on opposing vertical sides of the stock and each pair of opposing limbs arranged in a horizontal plane.

0043Embodiments of crossbow assembly <b>10</b> may have accessories attached to the stock or rail. For example, some embodiments may include any or all of the following: a scope, a dry-fire prevention mechanism, a safety, a cocking mechanism, one or more stabilizers, a pole, bipod or tripod mount, one or more vibration dampeners, a quiver, a stirrup, a bowstring drawing cocking aid, a flashlight, a laser pointer and/or a camera.

0044Components of crossbow assembly <b>10</b> may be made from any material that allows for effective operation of the crossbow. The material for different pieces of the crossbow assembly <b>10</b> may vary within the same embodiment. For example, in some embodiments, pieces of the crossbow assembly <b>10</b> may be made using metal, such as aluminum or steel, composites like carbon fiber or any of a variety of plastics or polymers and/or from wood. As would be understood by those of skill in the art, various fasteners or fastening methods may be used to assemble the components of crossbow assembly <b>10</b>, but have not been illustrated or discussed in detail.

0045While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.